\begin{tikzpicture}
    \tkzDefPoints{2.1/2/A, 0/0/B, 3/0/C}

    \tkzDrawPolygon(A,B,C)
    \tkzLabelPoints[above](A)
    \tkzLabelPoints[left](B)
    \tkzLabelPoints[right](C)
\end{tikzpicture}

